The presence and growth of certain microorganism in commercial process systems is an ongoing challenge. Many of the various stages of commercial process systems contain a variety of conditions having different amounts of water, nutrients, heat, shelter, anchoring substrates, chemical conditions, and/or an absence of predators, which often function as environmental niches suitable for colonization by all sorts of microorganisms. Population growth by these microorganisms often poses a number of problems including degrading process functions and fouling the end-products.
One such problem is microorganism induced crust deposit formation. Crust is the accumulation on a surface of an item present in a commercial process system of a rigid solid composition comprising deposited organic and/or inorganic material. The crust can be secretions and/or colonies of microorganisms themselves. In particular crust can include or consist of the accumulation of one or more kinds of hard shelled and/or chitin bearing and/or coral organisms. Crust can have many negative impacts on systems such as decreased operational efficiency, premature equipment failure, loss in productivity, loss in product quality, and increased health-related risks. Worst of all crust must often be physically removed by scraping or other physical means and this requires expensive shut downs or disassembly of part or all of the process system.
Another problem microorganisms pose is through the formation of biofilms. Biofilms are layers of organic materials comprising microorganisms or exopolymeric substance secreted by microorganisms, which aid in the formation of microbial communities. Biofilms can grow on the surfaces of process equipment as well as in pools of fluid. These biofilms are complex ecosystems that establish a means for concentrating nutrients and offer protection for growth. Biofilms can accelerate crust, corrosion, and other fouling processes. Not only do biofilms contribute to reduction of system efficiencies, but they also provide an excellent environment for microbial proliferation of other microorganisms including pathogenic organisms. It is therefore important that biofilms and other fouling processes be reduced to the greatest extent possible to maximize process efficiency and minimize the health-related risks from such pathogens.
Several factors contribute to the extent of biological contamination and govern the appropriate response. Water temperature; water pH; organic and inorganic nutrients, growth conditions such as aerobic or anaerobic conditions, and in some cases the presence or absence of sunlight, etc. can play an important role. These factors also help in deciding what types of microorganisms might be present in the water system and how best to control those microorganisms. Proper identification of the microorganism is also crucial to responding appropriately. Differences regarding whether the microorganisms are plants, animals, or fungi, or if they are planktonic or sessile determines how effective various biocontrol strategies will be. Because different microorganisms induce different problems, proper identification is crucial to properly remediating unwanted microbial effects. Finally because chemically caused problems cannot be remediated with biocides, it is also necessary to identify which problems have non-biologically based origins.
One category of matter commonly used to respond to micro-organism infestations is oxidants. Oxidants, such as sodium hypochlorite, are highly reactive and effectively “burn” away the cell walls of many microorganisms. Unfortunately because they are so reactive such oxidants often either lose effectiveness very quickly or they corrode or otherwise interact harmfully with other components or materials used in commercial process systems.
As a result, a number of technologies have been developed to stabilize oxidants. Some methods are described in U.S. Pat. Nos. 5,565,109 and 7,776,363. Such stabilization results in a countering of the so-called oxidant demand effect. In an oxidant demand effect reaction, because the oxidant is in the presence of something that it is highly reactive with, the oxidant tends to rapidly react and become unavailable for use as a biocide. By stabilizing oxidants, the oxidant remains present in the system for a longer period of time and is capable of suppressing microorganisms for an extended period of time.
In the biological world, however the demise of one organism often means a niche becomes available for another organism (which was previously suppressed by its now dead neighbors) to colonize. This in fact is often the case in process water treated with stabilized oxidant biocides. Many organisms (such as for example Sphingomonas sp., Acinetobacter, and Flavobacterium) secrete chemicals which can destroy the oxidant stabilizers and once their former competitors are killed off by the stabilized oxidants, they are capable of colonizing those environments despite the presence of the stabilized oxidants. As a result methods and apparatuses are needed to follow up after treating a commercial process system with a stabilized oxidant biocide to ensure these organisms have been eradicated.
Thus, it is clear that there is clear utility in novel methods and compositions for the follow up to stabilized oxidant biocide treatment of a commercial process system. The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “Prior Art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 CFR § 1.56(a) exists.